As a successor of W-CDMA and HSDPA, a communication scheme called Evolved UTRA (E-UTRA) is being studied. The E-UTRA is a radio access scheme that supports a plurality of bandwidths in an extensible manner, and that supports bandwidths from 1.25 MHz up to 20 MHz while maintaining compatibility with the existing 3G scheme.
In the existing W-CDMA, a single bandwidth of 5 MHz is supported in a same system, channels of uplink (from base station to terminal) and downlink (terminal to base station) are allocated so that data to be transferred is transmitted.